A nonvolatile memory device that is electrically erasable and programmable can preserve data stored therein even when it is not provided with power. Particularly, a NAND type flash memory can be inexpensive because it has a string structure in which a plurality of memory cells are connected in series. Thus, the NAND type flash memory can be used as a data memory in various portable devices.
Systems employing a nonvolatile memory device utilize configuration information, and thus operations for setting configuration information suitable for the systems are performed when the systems power-up. The configuration information includes synchronization latency, MRS, burst read latency, burst write latency and so on.
A general method of setting configuration information of a nonvolatile memory device includes storing the configuration information in a configuration register. However, this method records the configuration information whenever the system using the nonvolatile memory device powers-up thus making it inconvenient to set the configuration information. Furthermore, the configuration information can be changed in spite of a case that the configuration information should not be changed in view of security.
With the development of nonvolatile memory technology, nonvolatile memory devices capable of storing multiple bits in a single memory cell have become widely used. A single memory cell of the nonvolatile memory can store a single bit or multiple bits, and thus a single-bit region and a multi-bit region of a nonvolatile memory cell array can be set in a system using the nonvolatile memory. In this case, memory cells corresponding to the single-bit region can each store a single bit and memory cells corresponding to the multi-bit region each store multiple bits.
A method of setting information for setting the single-bit region and the multi-bit region is similar to the method of setting configuration information. Accordingly, the information for setting the single-bit region and the multi-bit region and the configuration information can be simultaneously set or separately set. Specifically, when the configuration information includes the region setting information, all the memory cells of a nonvolatile memory can be set to a single-bit region and a multi-bit region whenever a system using the nonvolatile memory is in power-up mode, and then the region setting information is recorded in a configuration register. The region setting information represents a part of the memory cell array corresponding to the single-bit region and a part of the memory cell array corresponding to the multi-bit region.
When the configuration information and the region setting information are set using the aforementioned method, however, the configuration information can be externally changed. Furthermore, the configuration information may be corrupted due to signal noise. Accordingly, the system using the configuration information may operate erroneously.